Unusable application

[Lanhild]

I can't repro the issue on the demo server.

[joseph]

Out of ideas, since I can't reproduce this anywhere. You can contact me on support@ if you want me to debug on the server.

[klawitterb]

@joseph I've now also noticed problems with the docker registry. In my case I'm also running a builderbot on the same cloudron instance. Seems like it can't connect to the docker registry, my logs on the builderbot are simply saying:

Mar 28 08:42:05 build-1774683724218 Build stream finished
Mar 28 08:42:05 build-1774683724218 Pushing...
Mar 28 08:42:20 build-1774683724218 Push stream finished
Mar 28 08:42:20 build-1774683724218 Get "https://docker.apehost.de/v2/": net/http: request canceled while waiting for connection (Client.Timeout exceeded while awaiting headers)
Mar 28 08:42:20 build-1774683724218 Push failed

Probably not related I've also noticed that the logs on the docker registry container get spammed with this error:

Mar 28 08:46:32 time="2026-03-28T07:46:32.467979729Z" level=error msg="traces export: Post \"https://localhost:4318/v1/traces\": dial tcp [::1]:4318: connect: connection refused" go.version=go1.23.7 instance.id=401bc88b-1bfe-4713-ae09-1cffdf628884 service=registry version=3.0.0
Mar 28 08:46:35 2026/03/28 07:46:35 [info] 71#71: *109 client 172.18.0.1 closed keepalive connection

[Lanhild]

@klawitterb said:
Probably not related I've also noticed that the logs on the docker registry container get spammed with this error:

Mar 28 08:46:32 time="2026-03-28T07:46:32.467979729Z" level=error msg="traces export: Post \"https://localhost:4318/v1/traces\": dial tcp [::1]:4318: connect: connection refused" go.version=go1.23.7 instance.id=401bc88b-1bfe-4713-ae09-1cffdf628884 service=registry version=3.0.0

I'm also encountering these.

[robi]

Assuming it is listening on port 4318, you can't do https with localhost.

Dropping the 's' should work if the API route is available.

[girish]

@Lanhild https://git.cloudron.io/packages/docker-registry-app/-/merge_requests/15 . I think that probably fixes it per upstream reports - https://github.com/distribution/distribution/issues/4270 , https://github.com/distribution/distribution-library-image/issues/187 . I don't think this related to your original DNS issue though. This traces export is just some log spam .

[girish]

OK, with the update that log message is gone (in our registry)

[klawitterb]

Log spam seems to be gone now, still having trouble with the actual connection to the registry on my cloudron:

Docker registry resides on the same cloudron

[msbt]

@klawitterb try without https://

[klawitterb]

Without https:// I'm getting: Invalid serverAddress: socket hang up

[msbt]

You got a typo in there maybe, or a firewall?

[nebulon]

So it should work without https:// there so the socket hang up is the issue somehow. Can you telnet via ssh to the registry from that server?

[klawitterb]

Just tried, that just gives me a telnet: Unable to connect to remote host: Connection refused

[nebulon]

If docker.apehost.de is the actual server, then I am able to contact that app from here at least. Does it correctly resolve on the system where it fails?

[klawitterb]

From the server:
ping -n docker.apehost.de -> works
telnet idontexist.apehost.de -> Name or service not known
telnet docker.apehost.de -> connection refused
docker pull docker.apehost.de/path-to-exisiting-image -> Error response from daemon: Get "https://docker.apehost.de/v2/": context deadline exceeded (Client.Timeout exceeded while awaiting headers)

From my local machine:
docker pull docker.apehost.de/path-to-exisiting-image -> works just fine

[nebulon]

So then telnet docker.apehost.de 443 also times out I assume. Is hairpin correctly working for you? run cloudron-support --troubleshoot to see this

[klawitterb]

Indeed seems like hairpin doesn't work, from troubleshoot:
[FAIL] Could not load dashboard domain.
Hairpin NAT is not working. Please check if your router supports it

I just tried the good old have you tried turning it off and on again, interestingly troubleshoot now errors with:
[FAIL] Could not load dashboard website with loopback check

[klawitterb]

So decided to upgrade my server to Ubuntu 24 and its working now again.

[nebulon]

Strange how that would have affected it, but well glad it works

[Lanhild]

@nebulon I did the upgrade from Ubuntu 22 to 24 today. I confirm that it fixed the issue for me as well.